nerve A bundle of fibers that uses electrical and chemical signals to transmit sensory and motor information from one body part to another. The fibrous portions of a nerve are covered by a sheath called myelin and/or a membrane called neurilemma. (Note that entries for specific nerves can be found under the names of the…
nerve, pinched A compressed nerve, as between two vertebrae or within a joint, causing discomfort, pain, or impairment of sensation. Treatment involves physical therapy and sometimes surgery. See also nerve compression.
nerve compression ”Pinching” of a nerve that is due to too much pressure on it. For example, a woman’s sciatic nerve may be painfully compressed by the weight and position of the fetus during the latter part of pregnancy.
nerve growth factor A naturally occurring substance that enhances the growth and survival of cholinergic nerves.
nervous colon syndrome See irritable bowel syndrome.
nervous system The sum total of the tissues that use electrical and chemical means to record and distribute information within a body. The nervous system has two distinct parts: central and peripheral. The central part is made up of the brain and spinal cord; together they are the central nervous system (CNS). The peripheral part…
neural Having to do with nerve cells (neurons).
neural tube defect A major birth defect caused by abnormal development of the neural tube, the structure that is present during embryonic life that gives rise to the central nervous system. Abbreviated NTD. NTDs are among the most common birth defects resulting in infant death and serious disability. There are a number of different types…
neuralgia Pain along the course of a nerve; for example, with and after shingles. See also neuralgia, postherpetic.
neonatal Pertaining to the newborn period, specifically the first 4 weeks after birth.
neonatal jaundice See jaundice, neonatal.
neonatal mortality rate The number of children under 28 days of age who die, divided by the number of live births in that year.